The purpose of this study was to identify risk factors for the development of HIV-related neurological diseases, specifically HIV- associated dementia and HIV-associated predominantly sensory neuropathy. The cohort consisted of 116 individuals with advanced HIV-infection and closed to enrollment 12/31/96. Progression of symptoms of HIV- associated dementia and HIV-associated predominantly sensory neuropathy were monitored through neurological evaluation, routine lab work, neuropsychological testing, activities of daily living assessment and a depression questionnaire, every six months. Participants who were identified with possible HIV-related neurologic disease were offered the opportunity to participate in appropriate clinical trials referred for further clinical treatment, as needed.